Angiogenesis denotes a process for generation of new blood vessels which rarely happens under normal in vivo conditions, but which is essential for processes of embryogenesis, luteinization, and wound healing. A process of angiogenesis usually comprises decomposition of a blood vessel basement membrane due to a protease stimulated by an angiogenesis-accelerating factor, migration of blood vessel endothelial cells, proliferation, and tube formation by a differentiation of blood vessel endothelial cells to reconstruct a blood vessel, thereby producing a new capillary blood vessel. A process of blood vessel generation is known to be strictly controlled by various accelerating and inhibiting factors, such as growth factors, cytokines, lipid metabolites, and potential fragments of hemostasis proteins.
On the other hand, microRNA is small non-coding RNA which inhibits gene expression at a control step after the transcription. MicroRNA is composed of 18 to 25 nucleotides on average and forms a hairpin structure. It complementarily binds to a 3′-UTR portion of the sequence of a target gene to inhibit mRNA from decomposing or translating to a protein, and it has been known that at least about 5000 human genes are targets of microRNA. Functions of microRNA in vivo can be various, and for instance, include cell differentiation and proliferation, control of developmental stages and metabolism, angiogenesis, and apoptosis, depending on what type of target gene is eventually controlled. As such, importance of the functions of microRNA is increasing, and accordingly, related research is becoming more active.
Therefore, the present inventors intend to use microRNA, which is a factor controlling an angiogenesis mechanism, to accelerate angiogenesis.